Question

Could someone help me by answering all of this questions from Q7) A to D and Q8) A to C. Thank You

Q.C7 An 80 kg cyclist is riding her 15 kg bicycle down a hill with a slope of 12 degrees without pedalling or braking. The cyclist has a frontal area of 0.45 m and a drag coefficient of 1.1 in the upright position. Taking air density to be 1.25 kg/m2, and neglecting bearing friction and rolling resistance (a) Calculate the terminal velocity of the cyclist. (6 marks) (b) If the cyclist were to adopt the racing position, which has a frontal area of 0.4 m2 and a drag coefficient of 0.9, what would her terminal velocity be? (4 marks) (c) If the cyclist were to turn and travel uphill and maintain a constant velocity of 20 km/h, how much power would she have to produce in the upright cycling position? (6 marks) (d) How much less power would be required if the cyclist adopted the racing position? (4 marks) Additional Data Q.C8 (a) List all the mechanisms of heat transfer that can occur through the following A translucent solid A vacuum A flowing liquid A stationary gas (4 marks) (b) During a cold winter day, wind at 55 km/h is blowing parallel to a 4 m high and 10 m long wall of a house. If the air outside is 5 °C and the surface temperature of the wall is 12 °C, determine the heat loss from the wall by convection (10 marks) (c) What would the answer be if the wind velocity was doubled? (6 marks) Properties of air at the mean temperature p 1.25 kg/m3 k 0.024 W/m°C 1.8 x 10-5 kg/m.s Pr 0.73 Equations to note Critical Re:5x10s For Laminar Flow: h L N0.664 Re5 Pr For Turbulent Flow hl 0.037 Re Pr/ For Laminar and Turbulent Nu =-= 0.037(Re-871) Pri/3

Answer 1